Stop-motion device for sewing machines



Feb. 2, 1932. E. B. ALLEN 1,843,534

STOP MOTION DEVICE FOR SEWING MACHINES Filed July 12, 1930 5Sheets-Sheet l illlllllll lllllllflllllllll! dam/M1 Feb. 2, 1932. E. B.ALLEN STOP MOTION DEVICE FOR SEWING MACHINES Filed July 12. 1950 5Sheets-Sheet 2 gwuentoz Edward flAlZerz Feb. 2, 1932. E. B. ALLEN STOPMOTION DEVICE FOR SEWING MACHINES 5 Sheets-Sheet 5 Filed July 12, 1930duo emu Feb. 2, 1932. E. B. ALLEN 1,843,534

STOP M OTION DEVICE FOR SEWING MACHINES Filed July 12, 1950 5Sheets-sheet 4 l J0 t 1 Edward flAJZeiz Feb. 2, 1 932. E. B. ALLEN1,843,534

STOP MOTION DEVICE FOR SEWING MACHINES Filed July 12, 1950 5 Sh'eis Sheo5 f w A l ,1

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i 52 -i y e 57 I 34 l J0 4 w .1? 11 Q l g 1 56 A 5 4 43 I L rw- 10 J 94542\X\ 50 a I 35)?56 if 5 14 J1! 13 13 gwoemio o Edward flullleizPatented Feb. 2, iesz st sf Area? Free EDWARD B. ALLEN, or Nnwrown,oonnn'o'ricunnssienoa TO THE smennlivmnnracrumne COMPANY, or ELIZABETH,NEW JERsnY, A CORPORATION or NEW JERSEY Application filed July 12, 1930.erial No. 467,432."

This invention relates to stop-motion mechanism for sewing machines,more particularly of the type represented in the patent to Allenllo. 743,212, of Nov. 3, 1903, and has for an object to provide improved meansfor releasing or tripping the stop-motiondevice when the stop-cam bearsa predetermined relation to the stop-plunger, so that the stopplungerwill always initially engage the low point of the stop-cam withoutdragging over the inner face of the stop-cam or nickingthe' edge of thelatter. I

The lnventlon consists 1111 116 devices, comblnations and arrangementsof parts hereinafter described and claimed.

The several features of the invention and the advantages attainedthereby will be readily understood by thoseskilled in the art from? thefollowing descriptionof a preferred embodiment thereof taken inconnection with the accompanying drawings, of which Fig. 1

is a side elevation of a Singer 71-Class but-- tonhole sewing machineembodylng the in-- vention. Fig. 2 is a fragmentary top plan View of thebracket-arm of the machine; Fig. 3 is a detail view of the stitch-gearsof the machine. Fig.4; is a perspective view of the stop-cam element ofthe stop-motion device with which the machine is equipped. Fig.

- is a. bottom plan view of the rearward endthe stop-motion lever inrunning position throughout the sewlng perlod. Flg. 8 1s a section onthe line 8-8, Fig.7. Fig. 9 is a View similar to Figs.- 5 and 7 at thetime of the tripping of the stop-motion lever. Fig. is a section on theline 10-10,

Fig. .9. Fighll is a'view similar to Figs. 5, 7 and 9, but illustrat ngthe resettmg of the latch initially operated upon by the feedwheeltripping point and Fig. 12 is a section on the line 12-12, Fig. 11. I V

In the preferred embodiment of the inven tion illustrated, the machineisconstructed with a frame including the bed 1, standard 2, overhangingbracket-arm 3 and head 4 carry-. ing the usual reciprocating andlaterally vibrating needle 5 with which the complementa'ry shuttle 6cooperates to form stitches.

There is journaled in the bracket-arm 3, the main-shaft 7 having theusual needle and shuttle driving connections, the latter including thecrank 8 and .pitlnan 9 which opcrates the rocking-forked element 10 onthestationary shaft 11. The rocking element or fork lO embraces theblock 12 on the crankpin 13 carried by the crank-arm 14 fixed to theshuttleedriving shaft :15-and oscillates the latter in the usual manner-The' 'machine embodies the usual workclamp 16 and feed-wheel 17 whichmoves it over the bed 1' to place the stitches around the buttonholeeWhen the main-shaft 7 is running, the feed-wheel 17 has stepiby-stepmovements imparted to it by the usual pinand-star-wheelr drive 18 whichis connected throughthe usual reduction or stitch-gears 19 tothefeed-wheel-shaft 20.

The main-shaft 7 carries at its rearward end the usual tight and loosebelt-pulleys 21, 22',and a pinion 23 which meshes with a gear 24; ofdouble its size, which gear is connected through the usualbuffer-springs 25 to the stop-cam 26 which cooperates in the usualmannerwith the upwardly spring-pressed stop-plunger 27 carried by thetilting stopmotion lever 28 fulcrumed on trunnion-screws 29 and hasrigid. with it a forwardly extending arm 30 towhich is connected at 31 arod 32'extending downwardlythrough the bedl and apertured at 32 forconnection by a chain tothe'usual starting treadle. The stop-motionlever 28 is held in full line'or running position, Fig. 1, by alatch-arm 33 fulcrumed at 34: below the bed 1 and pressed by the spring35 into a notch 36 in the side ofthe rod 32. The stop-motion device, asabove described; is constructed substantially in accordance with thedisclosure of the Allen and Myers application, Serial No. 272,416, filedApr. 24, 1928. In the machine illustrated, however, the stop-cam 26 isof duplex construction, having two diametrical- 1y opposed stop-notches26 and two plunger depressing eccentric portions 26 having low points 26and let-in inclines 26".

Unlike stop-motions of this type heretofore constructed, the latch 33 isnot moved directly by a tripping point on the feed-wheel 17 to releasethe stop-motion rod 32, but is coupled by the action of a tripping pointon the feed-wheel to a reciprocating member actuated by the main-shaftwhich subsequently and at a predetermined position of the stop-cam 26,moves the latch 33 to release the stop-motion rod 32. The timing is suchthat one or the other of the let-in inclines 26 and adjacent low point26 is opposite the upper end of the plunger-rod 27,'as shown in Fig. 10,when the stop-motion lever 28 isreleased. Hence the initial engagementof the plunger 27 and stop-cam 26 will be a clean-cut one, with nodanger of the upper end of the plunger 27 striking and nicking the edgesor corners of the eccentric portions 26 of the cam.

Rigid with the hub of the rocking fork 10 is an eccentric 37 which isembraced by one end of a link 38 the opposite end of which is formedwith a slot 39 slidably engaging a stud-pin 40 fixed to one of the bedlegs 41. The link 38 is thus in constant reciprocation while themain-shaft 7 is running. Pivoted at 42 on the link38 is a latchtripperin the form of a catch 43 having a hook-shoulder 44 adapted, whenreleased, to directly engage the latch 33 and move the latter to releasethe stop-motion rod 32. The spring 45 urges the catch 43 in a directiontoward the latch 33.

During practically the entire portion of the sewing operation, the catch43 is detained in an idly reciprocating position, Figs. 5 and 6, belowthe latch 33, by engagement of the tail 46 of the catch 43 with thelatch 47 which is fulcrumed at 48 on the stationary frame-bracket 49 andyieldingly held by the spring 50 in contact with the stop 51 on thebracket 49. V

The link 38, being operated by the eccentric 37, performs one cycle ofmovement or one reciprocation per stitch-forming cycle and is definitelyrelated to the stop-cam 26 so as to occupy the same position in itscycle relative to a given cyclical or angular position of the stop-cam26.

There is adjustably mounted on the feedwheel 17 a tripping point 52which, at the completion of the sewing operation, engages the arm 53 ofthe latch 47 and moves the latter to the position shown in Figs. 7 and8, thereby releasing the catch 43 which springs into engagement with thelatch 33 and moves the latter to release the stop-motion rod 32 within aperiod of one stitch-forming cycle or less, following the instant it isreleased for operation. This provision makes for permanent accuracy inthe timing of the releaseof the stop-motion control lever 28 relative tothe angular position of the stop-cam 26. Figs. 9 and 10 show therelative positions of the parts at the instant of release of thestopmotion lever 28 and it will be observed that at this instant the lowpoint 26 and the letin incline 26 of the cam 26 are opposite the upperend of the stop-plunger 27 which is free to move cleanly intocooperative engagement with the plunger-depressing eccentric portion 26following which it is projected upwardly into the stop-notch 26 andarrests the rotation of the main-shaft 7.

The time of release of the stop-motion rod 32 by the latch 33 is thusentirely independent of the particular ratio of stitch-gears 19 employedand is bound to occur at a fixed predetermined position in therevolution of the main-shaft 7 and hence in a fixed predeterminedposition of the stop-cam 26.

There is mounted on the stop-motion latchrod 32 a bracket 54 on which ispivoted a tooth 55 internally biased by a spring 55, Fig. 5. In thestopping position of the parts, the tooth 55 is disposed below a lateralextension 56 ofthe tail 46 of the catch 43, Figs. 9 and 10. When thestop-motion latch-rod 32 is released, it is moved upwardly by its spring57, Fig. 1, to shift the stop-lever 28 to stopping or dotted lineposition. During this upward movement of the rod 32, the rounded upperedge of the tooth 55 engages the lateral extension 56 which first rocksthe tooth 55 on its pivot in opposition to its spring 55 until thetooth, in passing the lateral extension 56, kicks the latter upwardly,Fig. 11, or to the right, Fig. 12, sufficiently to reset the catch 43 inits lowered or idle position, which it occupies when the machine comesto rest, Figs. 11 and 12; the tooth-spring 55 being strong enough toreset the catch 43 in the, upward movement of the tooth 55. When themachine is restarted by the operator in pulling down on the rod 32, thetooth 55, in passing the lateral extension 56, idly deflect-s the lattermomentarily; the catch 43 immediately returning to the position shown inFigs. 11 and 12. The tooth 55 is yieldingly retained by its internalspring 55'. Fig. 5, in engagement with. the. stop 55", Fig. 8.

Having thus set forth the nature of the invention, what I claim hereinis 1. A sewing machine having, in combination, a frame including a bed,stitch-forming mechanism including. a reciprocating needle and shuttle,shuttle-driving mechanism, a work-clamp, a feed-wheel below said bed andconnections for moving said workclamp, a stop-motion device forcontrolling the period of operation of the stitch-forming mechanism,said stop-motion device includ-' ing a stop-cam, a tilting stop-motionlever shiftable between starting and stopping positions, a pull-rodconnected to said stopmotion lever and extending downwardly below saidbed, a latch adapted to engage said rod to hold the stop-motion lever instarting position, latch-tripping means below said bed and connected tosaid shuttle-driving mechanism and moving idly during the sewingoperation, and means including a tripping-point on said feed-wheel forrendering said latch-tripping means effective when the sewing operationis completed.

2. In a sewing machine, a frame including a bed, stitch-formingmechanism includ ing a shuttle, a shuttle-driving shaft, a rockingelement for actuating the shuttle-driving I shaft, a stop-motion devicefor the stitchforming mechanism, sa1d stop-motion device includmg acontrol rod extendlng downwardly through said bed, a latch engaging saidrod, an eccentric connected to said rocking element, a reciprocatinglink actuated by said eccentric, a latch-tripping element carried bysaid link, means for holding said element out of engagement with saidlatch during the sewing operation, and means for shifting said holdingmeans to release said element when the sewing operation is completed.

8. In a sewing machine, stitch-forming mechanism, a main-shaft, astop-motion device therefor including a stop-cam having a low pointfollowed by an eccentric'portion and stop-notch, a stop-plungercooperating with said stop-cam, a spring-biased lever carrying saidstop-plunger and movable under the influence of its spring transverselyof the plane of sa1d cam from a running position in which saidstop-plunger is out of range of said stop-cam to a stopping position inwhich said plunger is within range of said stop-cam, a single latch fordetaining said lever in running positon from the time the machine isstarted until said lever is finally released for cooperation of saidstop-plunger with said stop-cam, latch-tripping means running with themain-shaft and performing an idle cycle of movement for eachstitch-forming cycle throughout the sewing period, and means operatingat the'end of a sewing period to establish an operative connectionbetween said latch-tripping means and said latch, said latch-trippingmeans being timed to trip said latch when the low point of said I cam isin position to receive said plunger.

In testimony whereof I have signed my I name to this specification.

EDWARD B. ALLEN.

